Madonna has gone to extremes to promote her upcoming New Zealand shows: she's posted a photo of herself posing topless with a horse.

The pop megastar is currently in town ahead of two shows at Vector Arena on Saturday and Sunday nights, her first performances here in a career spanning four decades.

The shows are yet to sell out, but her latest tweet is bound to cause attention.

In it, the Like a Virgin singer posted a photo on Twitter of herself posing raunchily in front of a horse, and tells fans to "Giddy up".


The snap, showcasing Madonna's toned back, had one fan calling her the "queen of back muscles".

Around 170 crew are in town for Madonna's shows, who will perform on a huge crucifix stage set up at the venue.

She has a full band, 20 back-up dancers, and will perform 23 songs, according to some statistics recently released about the show.

She's rumoured to be staying at the Pullman Hotel, but has kept a low profile since arriving in the country earlier this week.